Link List

Wednesday, December 17, 2014

Are we still doing 'beanbag' eu(genetics)? Part III. Culpably ignored nuances?

Part I of this series was about the particulate view of genes and their role in evolution and the determination of traits that are here because they were screened by evolution. Many view all traits as being in this category, and genetic determinism of those traits to be very strong and specific. But the data are less clear by far than the commitment to that idea.

Ernst Mayr criticized the one-gene-at-a-time focus of much of population genetics as 'beanbag' genetics. Mayr said that this was wrong for reasons we mentioned in Part I. As we discussed there, JBS Haldane, one of the grand ol' men who developed population genetics, wrote in defense of the field, in response to Mayr's criticism.

Haldane was a highly educated, thoughtful, perceptive British biologist whose life was nuanced in many ways that make telling a clear-cut story difficult. He was brilliant and exceedingly skilled. But he was also a product of his times, as are we all. In the early 20th century he became a Marxist, as did many other British aristocrats, accepting all that implies about what determines the structure of human society. Marxism was materialist but it was about improvability of individuals--an egalitarian view that claimed that position in a class-based society was due to class, not inherent inferiority of the lower classes, and thus that social inequity could--indeed would be erased by the processes of history. At the time, the Soviet Union seemed a Great Hope to many in heavily unfair empirical Britain. That essential malleability was one reason that the Russian plant geneticist Lysenko rejected Mendelian/Darwinian models of genetics in favor of a more Lamarckian mode of inheritance by which plants could be conditioned to have desired properties, and those would then be inherited. That proved in many ways to be a disaster for the Soviet Union.

Nonetheless, Haldane, who was a leading popularizer of science in his day, published a collection of reprinted essays in 1932 entitled The Inequality of Man. Ironic for a Marxist, but he was not simplistic. He dealt with, and accepted, the idea of eugenics in those essays, and that was largely what the title referred to. He acknowledged the major role of environment in making people what they turned out to be. But he stressed that genetics was part of human makeup, too. Rather than a more balanced treatment, at points he lapsed into the aristocratic view about intelligence and in that sense, inherent societal worth. The upper classes were what they are because of their abilities, and were under-reproducing compared to the lower classes. He even wrote of society not having the guts to kill its lesser citizens: despite warning about too much stress on inherency, in one article he wrote:

"The danger to democracy to-day lies not in the recognition of a plain biological fact [of inherent inequality] but in a lack of will in certain countries to kill persons who obstruct the declared wishes of the majority of the people." Further, "The only clear task of eugenics is to prevent the inevitably inefficient one per cent of the population from being born, and to encourage the breeding of persons of exceptional ability where that ability is known to be hereditary." There should not be a democracy except of a better minority.

There is a mix of views in Haldane's chapters, ranging from the autocratic extreme to something more humane and nuanced. He discusses social class, race, and intelligence as related to achievement, and even within Europe he makes distinctions about intelligence between (guess who!) northern and southern Europeans. But he also promotes improved opportunities and acknowledges that we don't know the nature or extent of hereditary control of traits like intelligence. In these popularized articles on many sociocultural issues, he is a softened genetic determinist. Perhaps this could be a Marxist 'from each according to his abilities, to each according to his needs' view; but that was always paternalistic when pronounced from on high. Haldane, like many scientists who are given a public forum, strays far and wide beyond what he knows best, and nearly a hundred years on we can see his only too human opinions. Life is complicated!

In any case, though the rhetoric is generally changed, we see roughly the same spectrum of views today, but that is in many ways implicitly a bean-bag model of inheritance. In his day, the idea of identifying the genes that cause the traits of interest was technically not possible. Now, in the excitement of 'omic technologies, the beanbagger approach is more explicit, noting this or that genetic variant that causes some socially relevant behavioral trait. This viewpoint is widespread, despite some occasional caveats about complexity and even if there are many labs working on more integrative approaches to that complexity.

The difficulties
These are not simple issues. People are different in physical, metabolic, and behavioral ways and clearly genetic variation is involved. Depending on one's social politics, that can be a central or an uncomfortable fact. But let us assume, for the moment and for argument's sake, that all the genetic determinism that has been proposed were perfectly true. Then what?

The idea in the writings of various authors, from the past and today, is essentially about what 'we' should do to mold society this way or that. But who are that 'we'? They're the professors, politicians, and so on, who in positions of influence make the judgments about what 'we' as a society 'need' to do. 'We' want more intelligence and less addiction and crime (as defined by 'us', of course; usually 'we' aren't talking about white-collar crime). 'We' decide what would be 'good' for society and what should be discouraged. And there is always the temptation to attribute inherent causation to these differences.

So, for example, we decide what do to with (or to?) those of higher and lesser inborn intelligence. This is rather indisputably arrogant and presumptuous, isn't it? Or, perhaps, one can ask whether it is any different from what has gone on heretofore.

If the minority of the privileged have the power to decide on societal action, it is rather moot whether the criteria used to justify that action are presumed genotypic ones or just the arbitrary wielding of power. Does it matter whether Divine Right or 'good genes' is credited with the power of the elite, and the subservience of the rest? The powers-that-be define the value judgments.

Genotypes may have more, or less, determinative roles than is widely being claimed these days. Eugenics was a particular kind of social control, that had regularly dreadful, indeed lethal, consequences for many people for various reasons. But whether that was any worse than religious or other political dominance is an open question.

Does it matter if it's an ISIS member who chops your head off because of your religion, or a Nazi who gasses you because of your ethnicity, or a physician who decides what genotypes need to be screened prenatally and eliminated, or who gets educational resources?

We have our own personal view, which is that the data generally do not support the making of such decisions based on genotypes and their presumed predictive value--and decisions related to those genetic variants that really do have such value should only be made privately, rather than by public policy. But the public pays for the treatment of genetic disease, so at what point is coercion within the scope of such an idea?

It is not clear whether these issues really ever get 'solved', or whether rational, measured discussion is even possible. But it does seem clear that questions about how genes control, or don't control, the traits in organisms are worth understanding, rather than action being taken on vague assumptions about inherent causality before the questions are even answered.

3 comments:

DG
said...

"It is not clear whether these issues really ever get 'solved', or whether rational, measured discussion is even possible. But it does seem clear that questions about how genes control, or don't control, the traits in organisms are worth understanding, rather than action being taken on vague assumptions about inherent causality before the questions are even answered."

There has been some 'Twtterage' asking who of the Big Three founders of population genetics was more interested in additive vs epistatic effects. The answer, I think, is 'all of them'. Wright clearly dealt with interactions in his path models, but additivity in models such as the 'effective' number of alleles contributing to a quantitative trait.

Haldane as said in our posts, and in his 'beanbag defense' paper, acknowledged the importance of interactions.

Fisher's model of polygenes was basically additive I think, but his theorizing about the evolution of dominance perforce dealt at least with intra-locus interactions.

Crow was, as I recall, the one who most stressed that only additive effects have evolutionary importance (because alleles within and between genes were independently transmitted in haploid subsets); but this idea has been questioned and probably is less key in small populations.

And what about Crow and Kimura and neutral evolution? There, interactions would be ignored by most population geneticists who mainly worked on evolutionary changes related to selection.

Even Darwin, in trying to write a plausible theory of pangenesis dabbled with non-additivity, though additivity was in effect (implicitly) the basis of his theory. Mendel's theory was all about interaction, but within loci (in his pea work; he knew other traits did't behave that way)

This is a superficial answer, and one really needs to turn to historians.

I need to add that, now just having looked back at Fisher's rather (for me and many others) impermeable but landmark 1918 'polygenic control' paper, that he acknowledges both dominance and inter-locus interaction (he calls it 'epistacy').

Comments

We always welcome comments, but we moderate them to reduce spam, gratuitous unkindness and so forth. Because we moderate comments, they won't appear on the blog until one of us publishes them, but we try to do that in a timely way.

We've had to make a change to the commenting page. People had told us that Blogger was eating their comments, so now, rather than embedding comment editing with the posts, it has to be done on a separate, full page. Unfortunately, the 'reply' option has disappeared so comments will just follow one another. We'll see how this goes.